For months leading up to the Belmont Stakes, thoroughbred racing found itself under attack. The New York Times ran a front-page story examining the high fatality rate at U.S. tracks. People for the Ethical Treatment of Animals lambasted the deaths of three horses in the filming of the racing drama “Luck,” and the outcry led HBO to cancel the series. Politicians made an issue of safety in racing and urged stricter oversight.

Underlying all these criticisms was the assumption that some malfeasance is likely to be involved when horses get hurt or die — either through the profligate use of drugs or outright animal cruelty.

But the tendon injury that prompted the immediate retirement of I’ll Have Another underscored the more banal truth: Thoroughbred racehorses are fragile and injuries to them are commonplace. They have been bred for three centuries to produce maximum speed and stamina by carrying a powerful body on spindly, delicate underpinnings. Their ankles, knees and legs are always vulnerable. I’ll Have Another was a different case only because his injury made front-page headlines and because it made more sense to retire a colt with future stud value than to bring him back to competition next year.

Because of the animals’ fragility, thoroughbred trainers everywhere do what Doug O’Neill, the trainer of I’ll Have Another, was doing at Belmont Park all week. They watch intently. They watch how a horse moves when he walks and gallops; they observe his demeanor and his eating habits; they examine his legs looking for any abnormality. Whether a trainer is managing a potential Triple Crown winner or a $10,000 claimer who might help pay the month’s bills, he knows that the most important part of his job is to detect potential problems before they turn into big — or even catastrophic — issues. Only the most irresponsible trainers would thrust an injured horse into battle.

O’Neill said at a news conference Friday that he had detected a slight change in I’ll Have Another’s demeanor this week — “He’s been a little quiet” — but that his legs had looked perfect until Thursday morning. He perceived a “loss of definition in the left front leg” but thought that the colt looked normal on Friday and sent him to the track for his morning exercise. But after the gallop, O’Neill said, “You could tell that the swelling was back.” He summoned the vet, and soon he learned that his hopes of training the first Triple Crown winner since 1978 were gone.

Owner J. Paul Reddam gave his trainer full credit for his vigilance. “The horse is not lame,” Reddam said. “He could have run tomorrow. You wouldn’t have known a difference had he not looked at it. So Doug, through extreme caution about the horse, had the vet come over and scan him.”

Reddam surely made a point extolling O’Neill in response to the avalanche of denunciations his trainer had received since winning the Kentucky Derby. While the issues of horse safety and the overuse of drugs had been boiling before the Derby, O’Neill’s success let the sport’s critics put a face on the abuses in horse racing.

When New York authorities announced they would stable all of the Belmont Stakes runners in a special detention barn, the New York Times reported that the action was taken “to ensure that I’ll Have Another’s bid to sweep the series is contested . . . without illegal drugs.” It explained: “O’Neill has racked up multiple violations in a handful of states and was suspended for 45 days by California regulators for yet another violation.”

O’Neill sounds like an arch-villain until one looks at the details of his violations. Racing fans can readily recognize the form of horses whose trainers are cheating with drugs; it is marked by sudden improvement that defies all logic. O’Neill’s horses never look like this — not even in the cases that earned him a penalty. The 45-day ban was for a too-high level of carbon dioxide, which can be a sign of the illicit procedure known as “milkshaking” but can also be the result of many other factors (such as dietary supplements or Lasix.). California officials handed out the suspension because rules are rules, and those rules need to be enforced to stop milkshaking. But they determined that O’Neill’s runner “had not been milkshaked and there was no evidence of any intentional acts on the part of O’Neill.” Yet media continued to cite this case as Exhibit A to prove that O’Neill’s presence was a blight on the Triple Crown.

There was nothing in O’Neill’s handling of I’ll Have Another or his comportment throughout the Triple Crown series that would confirm this caricature.

He managed his horse flawlessly. He withstood calumny with more grace than most human beings could muster. And when he was deprived of his shot at the greatest prize in American racing, he took the setback calmly and without self-pity. “It’s far from tragic,” he said, “but it’s very disappointing.” Like every other member of his profession, he understands that injuries and disappointments are an unavoidable part of the game.

For Andrew Beyer’s previous columns visit washingtonpost.com/beyer.

More on the Belmont Stakes:
I’ll Have Another is scratched from field
Jenkins: Horse racing needs fixing
2012 Belmont Stakes field
Triple Crown dream comes to end
I’ll Have Another’s run ends in barn, not track